A 14-year-old patient complains of alopecia foci on his scalp. The patient has been presenting with this condition for 2 weeks. Objectively: on the scalp there are several small oval foci with blurred margins. The skin in the foci is pink-red, the hairs are broken off at 4-5 mm length or at skin level. Under Wood's lamp there are no foci of green luminescence detected. What disease is it?